Sign post support



FIG. 1 is an isometric view of a sign post support, showing my new design;

FIG. 2 is a left side elevational view, the right side being a mirror image thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof. 

The ornamental design for a sign post support, as shown and described. 